1. Field of the Invention
The disclosed embodiments of the present invention relate to a filtering device, and more particularly, to a filtering device with low-pass and band-pass filtering functions.
2. Description of the Prior Art
In conventional wireless transceiver systems, when the wireless transceiver system operates in a receiving mode, a filter is usually employed to filter received wireless signals in order to generate a filtered signal for further signal processing in the transceiver system. On the other hand, when the wireless transceiver system operates in a transmitting mode, a different filter is employed to perform the filtering process in order to generate a wireless signal for transmission. Generally speaking, the aforementioned two filters exist independently to avoid interference and/or crosstalk between the receiving and transmitting signals. However, installing two independent filters in one wireless transceiver system consumes a larger area (e.g., a larger area in an integrated circuit), and thus increases the cost of the conventional wireless transceiver system. Therefore, the design of a filter circuit in a wireless transceiver system with lower cost is a significant concern in this pertinent field.